Refillable fuse



J. H. HICKEY REFILLABLE FUSE Oct. 9, 1928.

Filed Sept. 29, 1926 "Innwununnll' UIN Patented Oct. 9, 1928. y

UNITED STATES JOHN H. HICKEY, OF SAN FRANCISCO, CALFORNIA.

mszrILLAnLr.k FUSE.

. Application filed Septemlier29, 1926. SeralNo. 138,433.

My invention relates to improvements in refillable fuses wherein a transparent Vfuse containing shell is arrangedto be used in connection with a protective cover and de* tachable contact forming caps to facilitate the inspection of fuses and to effect economy in the replacing of blown fuses.

The presentinvention isan improvement over the device disclosed in my co-pending application, Serial No. 127,336, filed August 5, 1926, and consists of an improved construction and arrangement of elements adapted to obtain increased economy in manufacture and to facilitate and simplify the initial assemblyv and refilling of the fuse.

The primary object of the present invention is to provide an kimproved construction for refillable fuses. Y

Another' object is to provide an improved construction which may be manufactured and assembled economically.

A further object is to provide an improved construction which will give increased strength and which may be assembled without subjecting any portion of the fuse or` shell to internal strain. v

Another objectis to provide an improved construction whereby the shell may be removed by a simple loosening of a single set screw upon each end of the fuse and without the removal of any nut or other element likely to be lost. y

A still further object is tok provide an improved construction which 'does not require that the parts be finished to a close degree of accuracy, and which can be assembled without stressing any member ofthe fuse.

I accomplish theseand other objects by means of the improved device disclosed in the drawings forming a part of the present application wherein like characters of reference are used to designate similar parts throughout the speciiication and drawings and in which, y

Fig. 1 is a side elevation of my improved refillable fuse.

Fig. 2 is a longitudinal section taken'V at right angles to the position shown in Fig. 1.

Fig. 3 is an end elevation of the fuse drawn upon a larger scale.

Fig. il is a transverse section taken upon the line ll--fl of Fig. 2 in the direction indiecated, and Y Fig. 5 isa sectional detail showing the manner in which the evacuating tube is mounted and closed for sealing.

Referring to the drawings the numeral 1 is used to designate in'general a transparent shell, preferably made of glass tubing of a desired size. Vithin the transparent shell are mounted a pair of conductors, each comprising a disc portion 2 of a diameter sub stantially equal to the inside diameter ofthe shell 1, and a stem portion 3 extending outwardly from the ends of the shell. Lugs 4 extend inwardly from the portions 2 and are arranged to be connected by means of a fusi# ble conductor 6 of predetermined current carrying capacity; `said conductor 6 `beingY riveted or otherwise secured between the lug portions 4 of the conductors before said conductors are assembled into the tube. n

The disc portions 2 are arranged to normally occupy positions in spaced relation connected into the shell 1 through one of the discs 2, said tube being preferably made of lead or other pliant metal and isextended outwardly sufiicently to receive a connection to a pump by which the shell can be evacuated. After the ends of the shell have been sealed with cement, the air is exhausted from the shell through the tube 7, which is then collapsed, asvshown in Fig. 5, preferably at a point inside of the `end of the shell with suiiicient pressure to effect a complete closure. The outer end of the tube is then cut off and the end of the tube permanently sealed by solder or by embedding within cementset to entirely close the end of the shell, -as shown in Fig. 2 of the drawings. A protective cover 8 is fitted around the outside of the transparent shell 1 to rein force and strengthen said shell and to guard against breakage and possible injury to operators inserting or removing the fuse from a fuse block. Openings 10 formed in the cover permit the fusible conductor 6 to be observed through the transparent shell 1.

Contact caps 9 are fitted over the ends of the shell land cover 8, said caps being provided with blades 11 arranged Vto engage the contacts ol' a fuse lilock, not shown. The caps lit neatly around the ends of the shell and cover, and have bayonet slots 12 formed therein to engage pins 13 secured upon the cover to normally hold the caps in assembled relation with the shell. Lugs 14e are formed in central position upon the ends of the caps, said lugs and the blades 11 acent thereto being' recessed as at 16 to receive the outwardly extending,- ends of the stems 3 of the conductors. Set screws 17 are tapped into the sides ot the lugs land arranged to he moved into locking; engagement with the stem portions 3 to detachably lock the caps in engagement with the shell 1V and the stems 3 and to form positive electrical contact with the conductor stems.

My improved tuse, constructed as above explained, is applied and used in the ordinary manner. lVhen in service, the fusible conductor is readily observable through the openings and transparent shell 1, and the inspection ot fuses and the locating of blown fuses rendered easy. llhen a blown 'fuse is located, it is refilled by retrieving the caps 9 and cover 8 and inserting` a new shell 1 provided with conducter members sealed into place as above explained. rThe caps are removed by simply loosening the setscrcws 17, then turning the caps to cause the pins 13 to be disengaged by the bayonet slots 12r The caps and cover are now applied upon the fresh shell and the set screws 17 tightened.

rlhe improved construction above explained is ot particularl advantage as the allowable error in constructing the shells and conductors is relatively large, the depth oi the recesses 16 being` made sutllcient to accommodate a considerable variation in the length ot the shell portions 1 and the conductor stems The expense of extreme accuracy is thus avoided and the task ot assembli 1, and refilling` is greatly simplified. Furthermore, no strain is imposed upon the transparent shell and breakage from internal stress is entirely avoided.

The useot metal cvacuating tube sealed into the end of the shell is also ot material advantage, as the expense of drawing a tip onto the glass shell and the breakage due to such process is avoided. Furthermore, the metal sealing tube can be entirely embedded within the cement fillings sealing; the ends of the shell, thereby avoiding possible breakage or leaking, and avoiding the necessity olf heating the shell for fusing.

The above described construction is, of course, subject to modilication as to the speciiiic details of construction and arrangement and l desire to avail myself of all such modiiications as may fall within the scope oi the appended claims.

Having; thus described my invention what I claim new and desire to secure by Letters Patent is: y

1. A retillable fuse comprising a shell; a pair of conductors mounted in longitudinal ly spaced relation within the shell, said conductors comprisingv discs fitted into the shell in spaced relation to the ends thereof, stems extending' outwardly lroxn the ends et the shell, and lugs extending inwardly7 trom the discs; a fusible conductor ot predetermined current carrying` capacity connected be tween the lugs; cement lillings set within the space between the discs and the adjacent ends ot the shell to seal the same; conductive caps mounted. upon the ends ol the shell and arranged to engage the contacts ot' a fuse block; said caps being recessed to receive the outwardly extending` ends ol the stems; and means iter detachably securing' the caps in connection with the shell and in electrical contact wit i the stems` 2. A relillable iuse con'iprising` a shell; a pair ot conductors mounted in longitudinally spaced relation within the shell, said conductors comprising; discs litted into the shell in spaced relation to the ends thereo't, stems extending outwardly from the ends et the shell, and lugs extending inw'vardly from the discs; a tusil'ile conductor ot predetermined current carrying capacity connected between the lugs; cement lillings set within the space between the discs and the adjacent enos oil the shell. to seal the same; conductive caps mounted upon the ends of the shell and arranged to engage the contacts ot' a ituse block, said caps being recessed to receive the outwardly extendingencs et the stems; means for detachably securing,` the caps in connection with the shell and in electrical contact with the stems; and means arranged to receive a. pump connection tor evacuating` the shell.

3. A reiillable fuse comprising a transparent shell; a pair of conductors mounted in longitudinally spaced relation within the shell, said conductors conugrising;` discs litted into the shell in spaced relation to the ends thereof, anc stems extending outwardly from the ends ot the shell; a 'fusible conductor oit predetermined current carryingi` capacity connected between the discs; cement Hllings set within the space between the discs and the ends of the shell to seal the ends oi the shell; a protective insulating` cover fitted around the shell, said cover having openings therethrough to permit the observation ot the iusible conductor through the transparent shell; conductive caps mounted upon the ends of the shell and arranged to engage the contacts of a fuse block, said caps being recessed to receive the outwardly extending; ends ot the stems; and means for detachably securing thc caps in connection with the shell and conductors.

4l. A rellable fuse comprisinga transparent shell; a pair or" conductors mounted in longitudinally spaced relation within the shell to seal the saine; and a collapsible tube opening into the shell through one of the discs whereby the shell may be evacuated, seid tube being adapted to be collapsed to seul the evacuated shell and arranged to have its outer end embedded within the cement filling.

l1. 'n u fuse, the combination with a` shell, of caps mounted upon the ends of the shell; outwrfdhr extending lugs carried upon the outer ends of the cups, said caps having openings opening outwardly from the shell through the lugs; current conchicting ineens extending through the shell and having en ds en.tendingv outwardly through the openings; and ineens carried by the lugs for detachably securing said ends in electrical Contact with the lugs.

l2. In a fuse, the combination with a shell, of caps mounted upon the ends of the shell; outwardly extending lugs formed upon the outer ends of the caps, said caps having openings opening outwardly 'from the shell through the lugs; current conducting means extending through the shell und having ends extending' outwardly through the openings; and set screws tapped into the lugs to deteohzibly secure the ends of the conducting ineens in electrical Contact with the lugs.

ln witness whereo'lE I hereunto set my signature.

JOHN H. HICKEY. 

